WiTricity - Wireless Electricity

Our  forefathers marveled  at  the  invention  of  glowing  light  bulbs  by

Thomas  Edison  in  1879.  However,  to  us  21st  centurions,  the  light

bulb  is  nothing  out  of  the  ordinary.  When  computers,  cellphones,

laptops, iPods, etc. were invented our antennas tweaked. Now this is

what  you  call  invention!  However,  as  time's  progressing  we  are

getting used  to  these devices.  In  fact, charging all  these appliances

has become so very cumbersome.

 

Each  appliance  has  its  own  set  of  chargers,  and with  every  family

member owning their cellphones, the drawers are overflowing with all

sorts  of wires. How many  times  have  you wished  if  there  could  be

some way to do away with all the wiry clutter? When you are on the

way to work and your cellphone beeps in hunger for a battery charge,

haven't  you wished  for  your  cellphone  battery  to  get  'self  charged'.

Well your plight has been heard by doctor 'WiTricity'. 

        

What is WiTricity? 

WiTricity is nothing but wireless electricity. Transmission of electrical

energy  from one object  to another without  the use of wires  is called

as WiTricity. WiTricity will ensure that the cellphones, laptops, iPods

and other power hungry devices get charged on their own, eliminating

the need of plugging them in. Even better, because of WiTricity some

of the devices won't require batteries to operate.

 

 What's the Principle behind WiTricity? 

WiTricity  -  Wireless  Electricity,  these  words  are  simpler  said  than

done.  The  concept  behind  this  fascinating  term  is  a  little  complex.

However, if you want to understand it, try and picture what I state in

the next few lines. Consider two self resonating copper coils of same

resonating  frequency  with  a  diameter  20  inches  each. One  copper

wire  is  connected  to  the  power  source  (WiTricity  transmitter), while

the other copper wire is connected to the device (WiTricity Receiver). 

The  electric  power  from  the  power  source  causes  the  copper  coil

connected  to  it  to  start  oscillating  at  a  particular  (MHz)  frequency.

Subsequently, the space around the copper coil gets filled with nonmagnetic

radiations.  This  generated magnetic  field  further  transfers

the power  to  the other copper  coil  connected  to  the  receiver. Since

this coil is also of the same frequency, it starts oscillating at the same

frequency as the first coil. This is known as 'coupled resonance' and

is the principle behind WiTricity.

 

The Brain behind WiTricity? 

Prof.  Marin  Soljacic  from  Massachusetts  Institute  of  Technology

(MIT),  is  the one who has proved  that magnetic coupled  resonance

can be utilized in order to transfer energy without wires. What's even

more  interesting  is  how  he  came  about  this  idea. Soljacic,  just  like

any  of  us  was  fed  up  of  his  'low  battery'  beeping  cellphone  and

wondered  just  like  any  of  us  if  there  was  a  way  to  get  rid  of  this

'charging  problem'. However,  here  is where  the  difference  between

Soljacic and any of us comes in. He didn't just stand there wondering,

instead  he  tried  to  figure  out  if  there  existed  any  physical

phenomenon which could be of some help. He remembered Michael

Faraday's discovery of electromagnetic  induction  (1831) and used  it

to come up with WiTricity.

 

MIT's Experiment: 

In 2007, Marin Soljacic led a five member team of researchers at MIT

(funded by Army Research Office, National Science Foundation and

the Department of Energy) and experimentally demonstrated transfer

of electricity without the use of wires. These researchers were able to

light  a  60W  bulb  from  a  source  placed  seven  feet  away,  with

absolutely  no  physical  contact  between  the  bulb  and  the  power

source. 

The  first  copper  coil  (24  inches  in  diameter) was  connected  to  the

power source and  the second was connected  to  the bulb, and were

made  to  resonate at a  frequency of 10 MHz. The bulb glowed even

when  different  objects  (like  a wooden  panel) were  placed  between

the two coils. The system worked with 40% efficiency and the power

that  wasn't  utilized  remained  in  the  vicinity  of  the  transmitter  itself,

and  did  not  radiate  to  the  surrounding  environment. 

 

Is WiTricity a New Concept? 

No, this concept of wireless electricity is not new. In fact it dates back

to  the  19th  century,  when  Nikola  Tesla  used  conduction-  based

systems  instead  of  resonance  magnetic  fields  to  transfer  wireless

power.  Further,  in  2005,  Dave  Gerding  coined  the  term  WiTricity

which  is  being  used  by  the  MIT  researchers  today. 

Moreover, we  all  are  aware  of  the  use  of  electromagnetic  radiation

(radio  waves)  which  is  quite  well  known  for  wireless  transfer  of

information.  In  addition,  lasers  have  also  been  used  to  transmit

energy  without  wires.  However,  radio  waves  are  not  feasible  for

power transmissions because the nature of the radiation is such that

it spreads across the place, resulting into a large amount of radiations

being wasted. And  in  the  case  of  lasers,  apart  from  requirement  of

uninterrupted  line  of  sight  (obstacles  hinders  the  transmission

process), it is also very dangerous.

 

What's so Unique about Soljacic's experiment?

 What Soljacic's  team  has  done  is  that  they  have  specifically  tuned

the transmitting unit to the receiving device. The transmission is also

not hindered by the presence of any object in the line of sight. If the

object to be charged is in the vicinity of the WiTricity source, then the

energy transfer will undoubtedly take place.

 

In  this  'coupling  resonance'  system,  the  electric  energy  that  is  not

used  up  by  the  receiver  does  not  get  radiated  into  the  surrounding

environment,  but  remains  in  the  vicinity  of  the  transmitter.  This

ensures safety as well as minimal wastage of power. One of the five

researchers, Dr. Aristeidis Karalis says that their coupling resonance

system  is  one  million  times  more  efficient  as  compared  to  that  of

Nikola Tesla.

 

 Why was WiTricity not Developed before?

 It  is often said  'necessity  is  the best  teacher' and can be applied  in

this  case  as  well.  Only  in  this  century,  has  the  need  for  wireless

electricity emerged so rapidly, spearheaded by the agony caused by

the  cumbersome  charging  of  endless  devices.  Earlier  people  didn't

need it, so they didn't think about it.

 

How Safe is WiTricity?

 Human beings or other objects placed between  the  transmitter and

receiver  do  not  hinder  the  transmission  of  power.  However,  does

magnetic coupling or resonance coupling have any harmful effects on

humans?  MIT's  researchers  are  quite  confident  that  WiTricity's

'coupling resonance' is safe for humans. They say that the magnetic

fields  tend  to  interact  very weakly with  the  biological  tissues  of  the

body, and so are not prone to cause any damage to any living beings. 

What's the Future of WiTricity? 

MIT's WiTricity is only 40 to 45% efficient and according to Soljacic,

they  have  to  be  twice  as  efficient  to  compete  with  the  traditional

chemical batteries. The team's next aim is to get a robotic vacuum or

a laptop working, charging devices placed anywhere in the room and

even  robots  on  factory  floors.  The  researchers  are  also  currently

working  on  the  health  issues  related  to  this  concept  and  have  said

that  in  another  three  to  five  years  time,  they  will  come  up  with  a

WiTricity system for commercial use. 

WiTricity, if successful will definitely change the way we live. Imagine

cellphones, laptops, digital camera's getting self charged! Wow! Let's

hope  the  researchers will  be  able  to  come  up with  the  commercial

system soon. Till then, we wait in anticipation!